1. Field of the Invention
This invention relates generally to dampening circuits, and more particularly to a voltage reference overshoot protection circuit to dampen residual device, e.g. backplane, energy during switching operations.
2. Description of the Prior Art
Dampening circuits are well known in the art. The type of dampening circuit used is dependent upon the particular application. One application of dampening circuits is associated with unwanted ringing in a backplane. Recent advancements in backplane technology have made higher switching speeds possible. Modern trends indicate that improvements in switching speeds associated with backplanes will not only be desirable, but necessary, in order to accommodate the higher CPU speeds utilized in state of the art computers and related peripherals, among other devices.
One source of ringing in backplanes is associated with a low to high switching transition of a backplane driver voltage. Those skilled in the art of backplane technology have generally used edge rate control techniques to minimize the ringing in a backplane during a backplane driver output signal low to high switching transition. Edge rate control techniques are used to increase the rise and fall times of the backplane driver output signal. Although these known techniques have proven adequate in the past, such techniques are not able to accommodate the high speeds necessary to provide backplanes that are functional with higher speed computers, peripherals and other digital devices presently being designed and produced. These known edge rate control dampening techniques are problematic in that they reduce the bandwidth necessary to accommodate the higher data transmission rates and shorter propagation delay times generally associated with modern communication devices and protocols.
In view of the foregoing, a need exists for a dampening circuit capable of eliminating or substantially reducing unwanted ringing in devices such as backplanes, among other like devices. The bandwidth capabilities of such devices can then be optimized to accommodate higher data transmission speeds than that achievable using conventional edge rate control techniques generally known in the art.